Process Economics Program Report 52
Furnace Phosphorus and Phosphoric Acid
Published: July 1969
Out of the miracle glow "phosphorus mirabilis" discovered by Hennig Brandt in 1669 has come products containing or requiring phosphorus in the tens of thousands and potential compounds of phosphorus in the hundreds of thousands. Phosphorus has been found to be a vital component of plant and animal life.
However, the most rapid rate of growth for elemental phosphorus and products derived therefrom took place in the first half of the Twentieth Century. Since 1955, the rate of growth in the United States has slowed by almost one-half. The future for elemental phosphorus is far from clear. Wet process routes to phosphoric acid have bypassed phosphorus and taken over most of the rapidly growing fertilizer markets. Moreover, pollution problems are threatening existing large volume outlets for elemental phosphorus. On the other hand, some view new developments in nuclear power and in construction materials as a possible key to an acceleration of the elemental phosphorus growth rate.
The object of this report is to evaluate the costs and technology for the production of elemental phosphorus by conventional electric furnace methods, as well as for the conversion of this phosphorus to phosphoric acid. These methods are compared with previous studies of wet processes for phosphoric acid to obtain some impression of the relative future importance of these two routes to phosphoric acid. Possible alternatives to the electric phosphorus furnace, including the blast furnace and the fuel furnace, as well as other research suggestions, are discussed; from these, a fuel furnace process is distilled that appears to offer the most potential. A scheme for the joint production of phosphoric acid and by-product hydrogen from elemental phosphorus is also appraised. Other possible by-products are briefly mentioned.